1. Field
Embodiments of the invention relate to the field of electronic image sensors; and more specifically, to electronic image sensors with means for attenuating spurious reflected light.
2. Background
Electronic image sensors allow images to be captured in electronic form. Such sensors replace film in digital cameras and allow a camera function to be added to a variety of electronic devices such as cellular telephones, computers, and personal digital assistants. Image sensors are generally provided in the form of image sensor assemblies. The light that forms the image must fall on a light receiving surface of an image sensor die to capture the image. Therefore the image sensor die is provided in a package that is covered by a material that allows passage of image forming light through to the light receiving surface. An image sensor assembly may include the image forming optics or may provide the image sensor to be used with external optics.
The image sensor die is often attached adjacent to a lower end of a cavity in the package. The cavity will often have vertical walls adjacent the image sensor die. Light can strike these vertical walls and be reflected onto the light receiving surface of the image sensor die and degrade the image. This reflected light may cause stray light to be cast toward the edge of the image.
It would be desirable to provide an image sensor assembly that reduces image degradation caused by light reflected from the vertical walls of the package cavity that houses the image sensor die.